Method for forming multilayer coating film

A method for forming a multilayer coating film comprising the steps of:

• (1) applying a base paint (X) to a substrate to form a base coating film,
• (2) applying an effect pigment dispersion (Y) to the base coating film formed in step (1) to form an effect coating film, the solids content of the effect pigment dispersion (Y) during coating being 0.2 to 10 mass %, based on the effect pigment dispersion (Y),
• (3) applying a black transparent paint (W) to the effect coating film formed in step (2) to form a black transparent coating film,
• (4) applying a clear paint (Z) to the black transparent coating film formed in step (3) to form a clear coating film, and
• (5) heating the uncured base coating film, the uncured effect coating film, the uncured black transparent coating film, and the uncured clear coating film formed in steps (1) to (4) to thereby simultaneously cure these four coating films;
• wherein the effect pigment dispersion (Y) contains water, a black pigment (A), a vapor deposition metal flake pigment (B), and a rheology control agent (C), and
• the black transparent paint (W) contains a black pigment (P),
• wherein the obtained multilayer coating film has:
• a Y5 value of 40 to 1500, where the Y5 value represents lightness in the XYZ color space,
• a Y5/Y45 value of 40 to 300, where the Y5/Y45 value is obtained by dividing the Y5 value by a Y45 value, which represents lightness in the XYZ color space,
• a Y110 value of 0.15 to 1.5, where the Y110 value represents lightness in the XYZ color space, and
• an HG value of 5 to 50, where the HG value represents graininess.

A method for forming a multilayer coating film comprising the steps of:

• (1) applying a base paint (X) to a substrate to form a base coating film,
• (2) applying an effect pigment dispersion (Y) to the base coating film formed in step (1) to form an effect coating film, the solids content of the effect pigment dispersion (Y) during coating being 0.2 to 10 mass %, based on the effect pigment dispersion (Y),
• (3) applying a clear paint (Z) to the effect coating film formed in step (2) to form a clear coating film, followed by heating,
• (4) applying a black transparent paint (W) to the coating film formed in step (3) to form a black transparent coating film, and
• (5) applying a clear paint (Z) to the black transparent coating film formed in step (4) to form a clear coating film, followed by heating;
• wherein the effect pigment dispersion (Y) contains water, a black pigment (A), a vapor deposition metal flake pigment (B), and a rheology control agent (C), and
• the black transparent paint (W) contains a black pigment (P),
• wherein the obtained multilayer coating film has:
• a Y5 value of 40 to 1500, where the Y5 value represents lightness in the XYZ color space,
• a Y5/Y45 value of 40 to 300, where the Y5/Y45 value is obtained by dividing the Y5 value by a Y45 value, which represents lightness in the XYZ color space,
• a Y110 value of 0.15 to 1.5, where the Y110 value represents lightness in the XYZ color space, and
• an HG value of 5 to 50, where the HG value represents graininess.